By faxing lines of malicious code disguised as an image file to printers, hackers can exploit the fact that no one usually checks content received over fax. The file then can be decoded and stored in the printer’s memory, which allows hackers to take over the machine and eventually infiltrate the entire computer network connected to the printer.

“Faxploit is far worse than any of the theoretical Spectre or Meltdown Attacks,” says Seth Majors, Director of Service Delivery at Onepath. “Once exploited, fax machines can be used as a beachhead into the rest of your organization.”

If you’re currently using a fax machine or all-in-one printer, here are some ways to protect yourself:

Patch Your Software – If available, work with the manufacturer of your printer to update the device’s firmware and mitigate the vulnerability.

Protect Your Network – Place vulnerable devices on a network that is separated and protected from your critical infrastructure.

Remove Your Device – Unless you need to send a fax, unplug the device from the phone line. If the device is required to always be available, then unplug the device from the network and patch as soon as it becomes available.

To maintain a high level of IT hygiene, stick to a frequent patching schedule and ensure proper segmentation of your infrastructure. If you have an HP printer, click here for a list of effected models and the firmware needed to protect them.